I recently bought a jon boat and the trailer lights didnt work. Well my buddy wired me some new lights up and they work fine untill you turn on the head lights on the truck. Also when you turn on a blinker it is crossing over and both will blink. Anyone know what is causing these problems I am not the best with lights but finding out they can be a pain.

Bad ground. Run a ground wire from the lights to the tow vehicle. do not rely on the ball and trailer frame as a ground.

i did run the ground because thats what i thought and it still did it :-/

That isn't a ground problem.  I don't know what the problem is, but it isn't a ground.

Sounds like a grade A clstrfk to me.  :-X

I would say to just get a whole new wiring kit, or light kit, they don't cost much and it will take care of all your problems for a while, might want to consider a LED light setup, costs a little more but well worth it

What kind of truck? Most newer vehicles require a tailer light adapter to connect them up. If the vehicle has separate turn and brake lights, your trailer shares turn and brake so blocking diodes are needed, the trailer adapter has these diodes built into it. They can be bought at most parts stores.

If your friend used an adapter, then you could have blown it or as mentioned, have a grounding problem. You need to make sure the white wire coming out of the connector is connected (clean connection) to the trailer frame. An the one on the vehicle is connected to the vehicle frame/metal body, again good clean connection, no paint or rust under the connections. Same with all the grounds on the lights, good clean connection to frame.

Most newer vehicles require a tailer light adapter to connect them up.  If the vehicle has separate turn and brake lights, your trailer shares turn and brake so blocking diodes are needed, the trailer adapter has these diodes built into it.  They can be bought at most parts stores.

Oh yea, I forgot about those. My vehicles do not need them. I did have to put one in neighbors van so he could tow his jet ski. a sure way to tell if you need one is if your turn signals on the back are yellow. But they could be red as well.

I used this one http://www.trailerwiring.com/cgi-bin/view.cgi?part=48915

They're others you can use.

Try going to this site it should help you out.

www.accessconnect.com/trailer_wiring_diagram.htm

Check the ground on your trailer. This happened to me and I was told  to do that very same thing and I insisted I had a good ground.......Well further investigation revealed that I had grounded to good metal at  the front portion of the trailer. The problem was the trailer was actually two sections bolted together and for whatever reason the ground didn't transfer through the bolted sections. Bottom line, the ground wire from your vehicle has to to be grounded (to bare metal) to the section of trailer your lights are grounded to. Check all that first Since it's the easiest, then look at the wiring at your hitch connection. If you are having any of the same luck I had you won't have to go that far. Good luck.